#pragma once #include "types.hh" #include "hash.hh" #include <string> #include <future> namespace nix { struct DownloadRequest { std::string uri; std::string expectedETag; bool verifyTLS = true; enum { yes, no, automatic } showProgress = yes; bool head = false; size_t tries = 5; unsigned int baseRetryTimeMs = 250; DownloadRequest(const std::string & uri) : uri(uri) { } }; struct DownloadResult { bool cached = false; std::string etag; std::string effectiveUrl; std::shared_ptr<std::string> data; }; class Store; struct Downloader { /* Enqueue a download request, returning a future to the result of the download. The future may throw a DownloadError exception. */ virtual void enqueueDownload(const DownloadRequest & request, std::function<void(const DownloadResult &)> success, std::function<void(std::exception_ptr exc)> failure) = 0; std::future<DownloadResult> enqueueDownload(const DownloadRequest & request); /* Synchronously download a file. */ DownloadResult download(const DownloadRequest & request); /* Check if the specified file is already in ~/.cache/nix/tarballs and is more recent than ‘tarball-ttl’ seconds. Otherwise, use the recorded ETag to verify if the server has a more recent version, and if so, download it to the Nix store. */ Path downloadCached(ref<Store> store, const string & uri, bool unpack, string name = "", const Hash & expectedHash = Hash(), string * effectiveUri = nullptr); enum Error { NotFound, Forbidden, Misc, Transient, Interrupted }; }; /* Return a shared Downloader object. Using this object is preferred because it enables connection reuse and HTTP/2 multiplexing. */ ref<Downloader> getDownloader(); /* Return a new Downloader object. */ ref<Downloader> makeDownloader(); class DownloadError : public Error { public: Downloader::Error error; DownloadError(Downloader::Error error, const FormatOrString & fs) : Error(fs), error(error) { } }; bool isUri(const string & s); /* Decode data according to the Content-Encoding header. */ ref<std::string> decodeContent(const std::string & encoding, ref<std::string> data); }